The present invention relates to implantable electrode leads generally and more particularly relates to tools for assisting in the implantation of electrode leads.
Implantable electrode leads employing helical fixation members which are screwed into body tissues have been employed for many years to pace the heart and to stimulate other locations within the body. Most typically the fixation helix also serves as the electrode. Examples of such leads include those described in U.S. Pat. No. 3,737,579 issued to Bolduc, U.S. Pat. No. 4,066,085 issued to Hess and U.S. Pat. No. 5,143,090 issued to Dutcher et al., both of which are incorporated herein by reference in their entireties. Typically, these leads are implanted using a tool which grips the lead adjacent its distal end and are be employed to twist or screw the fixation helix into body tissue. Typically, these tools have taken the form of elongated rods or shafts which have a mechanism at their distal end for gripping the lead adjacent the electrode. The tools may also have grooves or other mechanisms for locating the lead body, along their length. Such tools are disclosed in the above-cited Bolduc and Dutcher et al patents and in U.S. Pat. No. 4,299,239 issued to Weiss et al., U.S. Pat. No. 4,271,846 issued to Little and U.S. Pat. No. 4,207,903 issued to O'Neill. A disadvantage of these tools is that they are best suited for implanting electrodes in those circumstances in which the area to which the electrode is to be attached is readily accessible to the physician. For example, as discussed in the above cited patents, the tools may be used to attach lead to the anterior surface of the heart during a full or modified thoracotomy. These tools, unfortunately, are not as readily useful in conjunction with implanting leads in less readily accessible sites, such as the posterior surface of the heart.